[web] More link fixes.

web/content/docs/benchmarks/hydro-mechanics/hm-unconfined-compression.md

 +++
-project = "https://github.com/ufz/ogs-data/blob/master/HydroMechanics/Linear/Unconfined_Compression_early/square_1e2_UC_early.prj"
+project = "HydroMechanics/Linear/Unconfined_Compression_early/square_1e2_UC_early.prj"
 author = "Tianyuan Zheng"
 date = "2017-02-16T15:10:33+01:00"
 title = "Unconfined compression"

web/content/docs/benchmarks/thermo-mechanical-phase-field/thermo-mechanical-phase-field.md

 +++
-project = "https://github.com/ufz/ogs-data/blob/master/ThermoMechanicalPhaseField/cube_1e0.prj"
+project = "ThermoMechanicalPhaseField/cube_1e0.prj"
 author = "Xing-Yuan Miao"
 date = "2018-03-11T09:10:33+01:00"
 title = "Non-isothermal test"
@@ -52,4 +52,4 @@ $$
 \begin{equation}
 \nu(d) = \frac{3K-2Gd^2}{2(3K+Gd^2)}
 \end{equation}
-$$
+$$
\ No newline at end of file